Generally speaking, in the environment of workpiece production, the production speed of machinery is far greater than the speed of measuring the workpiece by a worker. The worker usually increases the measurement speed, which is, however, easy to cause that the measured value is not correct. An automatic measurement system may prevent the measure errors due to the worker. Nevertheless, when the workpiece is automatically produced, production errors may adversely affect the measurement result by the automatic measurement system. When the workpiece is measured by the worker, the worker may manually adjust the workpiece to prevent the production errors to affect the measurement of the unprocessed region. As a result, how to prevent the production errors from affecting the result of the automatic measurement is a main subject to research.